Non-parametric statistical techniques for estimation of regression coefficients and coefficient of variation in corporate finance

Predmet istraživanja disertacije je intervalno ocenjivanje regresionih koeficijenata u prostom linearnom regresionom modelu i kvadratnom regresionom modelu ako slučajna greška nema normalnu raspodelu i intervalno ocenjivanje mera disperzije ako osnovni skup ne sledi normalnu raspodelu. Ako su narušene polazne pretpostavke, proporcija simuliranih intervala za regresione koeficijente i mere disperzije može znatno odstupati od nominalnog nivoa pouzdanosti. U radu su razvijene originalne metode za intervalno ocenjivanje regresionih koeficijenata u prostom linearnom i kvadratnom regresionom modelu zasnovane na Edgeworth-ovom razvoju raspodele t statistika koje se koriste u pomenutim modelima. Dalje, predložene su transformacije metoda koje se koriste za intervalno ocenjivanje koeficijenta varijacije. Reč je o transformaciji zasnovanoj na odsečenoj sredini i bootstrap transformaciji. Validnost predloženih metoda proverena je kroz simulacije koristeći različite raspodele, kao i podatke u oblasti korporativnih finansija. Korporativne finansije obuhvataju praćenje efekata finansiranja kako bi se maksimizirala vrednost kompanije, kao i različite aspekte značajne za rast kompanije. Iz tog razloga, predmet razmatranja prilikom konstrukcije intervalnih ocena bili su podaci o indikatoru verovatnoće bankrotstva, količniku ukupnog duga, meri sistematskog rizika i dividendama. Utvrđeno je da su, u većini razmatranih slučajeva, proporcije simuliranih intervala zasnovanih na predloženim metodama bliže nominalnom nivou pouzdanosti u poređenju sa proporcijama intervala proučavanih u literaturi. Na osnovu rezultata dobijenih u empirijskom delu, date su preporuke za intervalno ocenjivanje koje se mogu koristiti za donošenje pouzdanih zaključaka, pre svega, u oblasti korporativnih finansija. Ključne reči: proporcija simuliranih intervala poverenja, nominalni nivo pouzdanosti, regresioni koeficijent, prost linearni regresioni model, kvadratni regresioni model, koeficijent varijacije, Edgeworth-ov razvoj raspodele t statistike, odsečena sredina, korporativne finansije.The subject of the research of dissertation is the interval estimation of the regression coefficients in the simple linear regression model and quadratic regression model if an error term does not have normal distribution and interval estimation of the measures of dispersion if the population does not follow normal distribution. If the initial assumptions are violated, the proportion of the simulated intervals for the regression coefficients and measures of dispersion can noticeably deviate from the nominal confidence level. The original methods for the interval estimation of the regression coefficients in the simple linear and quadratic regression model, based on the Edgeworth's expansion of the distribution of the t statistics which are used in the mentioned models, were developed. Further, the transformations of the methods used for the interval estimation of the coefficient of variation were proposed. It is about the transformation based on the trimmed mean and the bootstrap transformation. The validation of the proposed methods was checked through simulations using different distributions, as well as the data in the field of corporate finance. Corporate finance includes monitoring the effects of financing in order to maximize a company’s value, as well as various aspects important to the company’s growth. For that reason, the data on the bankruptcy probability indicator, total debt ratio, systematic risk measure and dividends were considered in order to construct the interval estimates. It was found that, in most of the considered cases, the proportions of the simulated intervals based on the proposed methods are closer to the nominal confidence level compared with the proportions of the intervals studied so far in the literature. Based on the results obtained in the empirical part, the recommendations for the interval estimation, which can be used to draw the reliable conclusions, primarily, in the field of corporate finance, were given. Key words: proportion of the simulated confidence intervals, nominal confidence level, regression coefficient, simple linear regression model, quadratic regression model, coefficient of variation, Edgeworth's expansion of the distribution of the t statistic, trimmed mean, corporate finance

Moral values in the internet architecture design

Filozofsko određenje interneta polazi od izbora pravog nivoa tehnološke apstrakcije na kome se može govoriti o njemu kao promenljivom tehnološkom sistemu, a isto tako i od izbora arhitekture kao objekta analize dizajna interneta. Arhitektura je sinonim za tumačenje interneta od strane inžinjera tj. mrežnih dizajnera, tokom koga su se oni upustili u kreiranje šireg viđenja o tome kako vide ili žele da vide, izgrade ili regulišu taj sistem. U originalnu arhitekturu interneta založene su vrednosti libertarijanske kulture i principi koji vode računa pre svega o što široj interkonekciji putem jedinstvenog seta protokola. Vremenom je internet zajednica morala da odustane od arhitekture mreže u korist postavljanja u centar pažnje velikog broja aplikacija. U toj post-arhitekturalnoj fazi, do filozofskog određenja interneta se dolazi kroz razmatranje pitanja vezanih za upravljanje internetom, njegovu materijalno-prostornu realizaciju i njegovu interakciju sa komercijalnom sferom. Upravljanje internetom, ma kako funkcionalno, nije sprečilo da se pojavi neupravljani internet tzv. tamni internet iliti mračna strana javnog interneta. Tamni internet je moguć zahvaljujući kriptografiji, i inherentna mu je subverzivnost. Iz tamnog interneta stiže ne samo ozloglašeni sajber kriminal, već i prodor istine zarad opšteg dobra tj. raskrinkavanje nadzora nad javnim internetom. Mapiranje interneta na planeti ukazuje da jedan mali broj lokacija prima, razmenjuje i transmituje veliki deo internet saobraćaja i komunikacija na planet

The school library in documents of Comprehensive curriculum reform 2016

Rad prikazuje ulogu školske knjižnice osnovne škole u nastavnom odgojno-obrazovnom procesu. Budući da je osnovna škola odgojno-obrazovna ustanova, a školska knjižnica njezin integralni dio, navode se obrazovni i odgojni zadatci. Prikazuje se opis definicija, djelatnosti i zadaća školske knjižnice kao i nositelja svih njezinih aktivnosti - školskoga knjižničara. Objašnjavaju se najvažnije odrednice Hrvatskoga nacionalnoga obrazovnoga standarda kao i Nacionalnoga okvirnoga kurikuluma kako bi se zaključilo što je Cjelovita kurikularna reforma 2016. godine naslijedila, a što novo donijela svojim Okvirnim kurikulumom. Kako je izrada Posebnoga kurikuluma školske knjižnice još nerealizirana, uloga se školske knjižnice promatra pomoću dokumenata Cjelovite kurikularne reforme, međupredmetnih tema Uporaba informacijske i komunikacijske tehnologije i Učiti kako učiti te nastavnoga predmeta Hrvatskoga jezika. Radom će se pokušati zaključiti na koji je način zastupljena školska knjižnica u dokumentima Cjelovite kurikularne reforme i koja su očekivanja u navedenim dokumentima od školskoga knjižničara. Također, analizom već postojećih dokumenata, pokušat će se odgovoriti je li potrebna izrada Posebnoga kurikuluma za školske knjižnice.The paper presents the role of a primary school library in educational process. Since primary school is an educational institution, and a school library is its integral part, educational objectives are named. Descriptions of the definitions, the work, and the objective of a school library are presented, as well as the person responsible for all of its activities the school librarian. The most important baselines of the Croatian National Educational Standard (CNES) are explained, as well as the National Curriculum Framework, to determine what the Comprehensive Curricular Reform 2016 inherited, and what new additions it brought with its Curriculum Framework. Since the making of the Special School Library Curriculum has not been realized yet, the role of a school library is observed by using the documents Comprehensive Curricular Reform, correlation topics The use of information and communication technology and Learning how to learn, and the school subject Croatian language. This paper will try to conclude the way the school library has been represented in the documents of the Comprehensive Curricular Reform and what the expectations of the school librarian are in the mentioned documents. Furthmore, with the analysis of existing documents, the paper will try to answer the question whether the making of the Special School Library Curriculum is necessary

Electrochemical and catalytic applications of cerium(IV) oxide

Cerium(IV) oxide is one of the most important rare earth metal oxides owing to its high oxygen storage and release capacity, as well as thermal and mechanical stability. Its various applications range from sensors, solid oxide fuel cells and supercapacitors to the most important catalytic application in three-way catalytic converters, oxidation of volatile organic molecules, water-gas shift reaction, etc. This short review article gives a brief introduction to rare earth metals, then describes in detail the properties of cerium(IV) oxide and ways to improve them, as well as presents an overview of the most important and current applications of cerium(IV) oxide. Finally, it gives an overview of the results obtained by our group regarding pure and doped cerium(IV) oxide for various applications

A new simple liquid chromatographic assay for gentamicin in presence of methylparaben and propylparaben

Gentamicin sulfate is a potent broad spectrum aminoglycoside antibiotic which is used against Gram- positive and Gram-negative bacteria. A simple, isocratic HPLC method for separation, identification and determination of gentamicin and parabens (methylparaben and propylparaben) was developed and validated. To our knowledge there is no report about simultaneous determination of those three ana- lytes in pharmaceutical products. The optimum chromatographic conditions were achieved on CN column with a mobile phase consisting of 0.15% triethylamine in 10 mM KH 2 PO4 aqueous solution (final pH 3.0 adjusted with H 3 PO 4 ) and methanol in the ratio 70:30 (v/v), providing selective quan- tification of analytes within 5 min. The method was successfully validated according to ICH guidelines acceptance criteria in terms of selectivity, linearity, accuracy, precision and robustness. The linearity of the method was proved in defined concentrations ranges for gentamicin (0.32–1.04 mg mL1 ), meth- ylparaben (0.0072–0.0234 mg mL1 ) and propylparaben (0.0008–0.0026 mg mL1 ). Relative standard deviations calculated for all analytes in precision testing were <2% (analysis repeatability) and <3% (intermediate precision). Recovery values were between 98.87% and 101.67%. Chromatographic pa- rameters are not significantly influenced by small variations of column temperature, pH and molarity of KH2 PO 4 . Finally, the method was successfully applied for quantitative determination of gentamicin and parabens in commercially available solution for injection. Proposed HPLC method is found to be promising in terms of simplicity, analysis times and non-use of derivatization and ion-pair agents

3D tehnika digitalne obrade svetlosti (DLP) primenjena u izradi dvoslojnih tableta: koncept kombinovane polipilule

Ever since 3D printing was introduced to the field of pharmacy, it has caused a paradigm shift from the manufacturing of large-scale to small batches of medicines tailored accordingly to the specific needs of patients. This study aimed to formulate and fabricate two-layered 3D tablets using the digital light processing (DLP) technique. Hydrochlorothiazide (HHT,5%,w/w) and warfarin sodium (WS,5%,w/w) were selected as model drugs. The printing process was initiated with 0.1% of photoinitiator, at a constant ratio of poly(ethylene glycol)diacrylate and poly(ethylene glycol) 400, 1:1, with the addition of water (10%,w/w). Single-layered tablets of 8.00 mm diameter and 1.50 mm thickness, containing HHT and WS respectively, were successfully printed, as well as combined two-layered 3D tablets, with each of the active substances in separate layers. Dissolution tests of single-layered tablets showed immediate, but incomplete release of WS (81.47±1.47%, after 45min), and prolonged and complete release of HHT (98.17±3.11%, after 8h), while significantly slower and incomplete release of both drugs from the combined two-layered 3D tablets was observed. The absence of drug-polymer interaction and presence of a layered cross-sectional tablet structure were confirmed. DLP technique enables simple and rapid fabrication of combined two-layered 3D tablets, while further optimization of formulation factors is necessary to achieve complete drug release.Uvođenje tehnologije 3D štampe u oblasti farmacije uslovilo je razvoj fundamentalnih promena, pri čemu serijska proizvodnja velikih šarži pretenduje da bude zamenjena malim serijama lekova prilagođenih prema specifičnim potrebama pacijenata. Cilj istraživanja bio je da se formulišu i izrade dvoslojne tablete primenom tehnike digitalne obrade svetlosti (DLP). Hidrohlortiazid (HHT, 5%, m/m) i varfarin-natrijum (WS, 5%, m/m) odabrani su kao model lekovite supstance. Proces štampanja sproveden je u prisustvu 0,1% fotoinicijatora, pri konstantnom masenom odnosu poli(etilen glikol)diakrilata i poli(etilen glikola) 400, 1:1, uz dodatak 10% vode. Jednoslojne 3D tablete prečnika 8,00 mm i debljine 1,50 mm, koje sadrže HHT, odnosno WS, kao i kombinovane dvoslojne 3D tablete, sa svakom od aktivnih supstanci u posebnom sloju, uspešno su odštampane. Prilikom ispitivanja brzine rastvaranja lekovite supstance iz jednoslojnih tableta, došlo je do trenutnog (81,47±1,47%, nakon 45 min), ali nepotpunog oslobađanja WS, i produženog i potpunog oslobađanja HHT (98,17±3,11%, nakon 8 h), dok je iz kombinovanih tableta zapaženo znatno sporije i nepotpuno oslobađanje obe lekovite supstance. Potvrđeno je odsustvo interakcija i prisustvo slojevite strukture. DLP tehnika pruža mogućnost jednostavne i brze izrade kombinovanih tableta, pri čemu je dalja optimizacija formulacionih faktora neophodna u cilju postizanja potpunog oslobađanja lekovite supstance

Segmentation and Classification of Bi-Rads Medical Images with the Imaging Biomarkers According To Level of Detail

Segmentation is one of the latest directions of digital imaging development, presented by partial segments which are parts of the same image. The currently used algorithms are rare and far from ideal. Depending on the situation, algorithms behave differently, so it is almost impossible to single out a unique conclusion. This paper gives a proposal for new segmentation techniques with the help of Imaging Biomarkers for the digital image processing with auxiliary Hybrid edge detection algorithm and especially a defined threshold of detection. Matlab software is used for giving a particular conceptual design of a partial display of images and for correlating adequate numerical methods of digital processing. The study results confirm the quality of the proposed algorithm and position it for practical use in classification of BI-RADS breasts classified by density

Modelling of hydrological processes in the catchment area of Lake Skadar

Rad se bavi modeliranjem hidroloških procesa u slivu Skadarskog jezera koji pripada prostoru Crne Gore. Ovo jezero i njegov sliv predstavljaju jedan od najznačajnijih prirodnih resursa u Crnoj Gori. Korišćen je postojeći model (MIKE SHE (DHI)) za simulaciju hidroloških procesa na slivu. Njegova primjena je pokazala neke limite koji se primarno odnose na nedostatak dovoljnog fonda raspoloživih ulaznih podataka. Poseban problem koji se pokazao jeste nedostatak podataka o režimu podzemnih voda kao jednog od ključnih faktora u modeliranju ukupnog vodnog bilansa na slivu. Ipak kalibracija modela je pokazala zadovoljavajuće rezultate i dovoljnu prihvatljivost modela tako da on može biti dobra osnova za buduće prognoze hidroloških veličina na slivnom području. Također, model je moguće i dalje nadograđivati s novim podacima i rezultatima, čim se za to steknu uvjeti.Paper deals with the modelling of hydrological processes in the catchment area of Lake Skadar in Montenegro. This lake and its catchment area is one of the most important natural resources of Montenegro. We used an existing model (Mike SHE (DHI)) to simulate the hydrological processes. Its implementation has shown some limitations that are primarily related to insufficient funds of available input data. A particular problem is the lack of data on groundwater regime as one of the key model and water balance factors. However, calibration of the model showed that the results obtained were sufficiently acceptable and that the model can be a good basis for future hydrological forecasts of the basin size. Also, the model can still be upgraded with the new data and results, as soon as the conditions call for it

Powder bed fusion–laser beam (PBF-LB) three-dimensional (3D) printing: Influence of laser hatching distance on the properties of zolpidem tartrate tablets

Laser sintering, known as powder bed fusion–laser beam (PBF-LB), offers promising potential for the fabrication of patient-specific drugs. The aim of this study was to provide an insight into the PBF-LB process with regard to the process parameters, in particular the laser hatching distance, and its influence on the properties of zolpidem tartrate (ZT) tablets. PHARMACOAT® 603 was used as the polymer, while Candurin® Gold Sheen and AEROSIL® 200 were added to facilitate 3D printing. The particle size distribution of the powder blend showed that the layer height should be set to 100 µm, while the laser hatching distance was varied in five different steps (50, 100, 150, 200 and 250 µm), keeping the temperature and laser scanning speed constant. Increasing the laser hatching distance and decreasing the laser energy input led to a decrease in the colour intensity, mass, density and hardness of the ZT tablets, while the disintegration and dissolution rate were faster due to the more fragile bonds between the particles. The laser hatching distance also influenced the ZT dosage, indicating the importance of this process parameter in the production of presonalized drugs. The absence of drug-polymer interactions and the amorphization of the ZT were confirmed